update

hard/591.tag-validator.go

@@ -0,0 +1,22 @@
+func isValid(code string) bool {
+	st := make([]string, 0)
+	for i, r := range code {
+		if 0 < i && len(st) == 0 {
+			return false
+		}
+		if code[i:i+9] == "<![CDATA[" { // Parse cdata
+			i = strings.Index(code[i+8:], "]]>")
+			if i < 0 {
+				return false
+			}
+			i += 2
+		} else if code[i:i+2] == "</" {
+			name := 
+		} else if r == '<' {
+			
+		}
+	}
+	return len(st) == 0
+}
+
+

hard/600.non-negative-integers-without-consecutive-ones.go

@@ -0,0 +1,20 @@
+func findIntegers(num int) int {
+	f := make([]int, 31)
+	f[0], f[1] = 1, 2
+	for i := 2; i < 31; i++ {
+		f[i] = f[i-2] + f[i-1]
+	}
+	cnt, pre := 0, 1
+	for k := 30; 0 <= k; k-- { // The highest bit is the sign of int32.
+		if (num>>uint(k))&1 == 1 {
+			cnt += f[k]
+			if pre == 1 {
+				return cnt
+			}
+			pre = 1
+		} else {
+			pre = 0
+		}
+	}
+	return cnt + 1 // Means num itself is also valid.
+}